Aircraft Fuel Systems Maintenance Exam – 100
Questions, Answers & Rationales
1–100
1. What is the primary purpose of an aircraft fuel system?
a. Provide lubrication to the engines
b. Cool the engine oil
c. Store and deliver fuel to the engines
d. Store, manage, and supply fuel to the engines at the correct
pressure and flow
Rationale: Aircraft fuel systems must ensure continuous, reliable
fuel flow at the correct pressure for safe engine operation.
2. Which fuel tank type is integral to the aircraft's structure?
a. Bladder tank
b. Integral tank
c. Rigid removable tank
d. Auxiliary tank
Rationale: Integral tanks are sealed sections of the aircraft wings
or fuselage used to store fuel.
3. What is the main advantage of bladder-type fuel tanks?
a. Ease of installation and maintenance
b. Highest fuel capacity
c. Lowest likelihood of leaks
d. Most resistant to contamination
Rationale: Bladder tanks can be removed or replaced easily,
reducing maintenance time.
,4. Microbiological contamination in aviation fuel is most common in
areas containing:
a. Pure fuel
b. Water and fuel interface
c. Fuel vapor
d. Additives
Rationale: Microbes thrive where water meets fuel, feeding on
hydrocarbons and causing corrosion.
5. The primary function of a fuel boost pump is to:
a. Remove water from fuel
b. Supply positive pressure to the engine-driven pump
c. Measure fuel temperature
d. Pressurize the fuel tanks
Rationale: Boost pumps ensure sufficient inlet pressure to
prevent engine pump cavitation.
6. A common cause of vapor lock in fuel systems is:
a. High temperatures causing fuel to vaporize
b. Low humidity
c. Excessive water in fuel
d. Overfilling fuel tanks
Rationale: Heat causes volatile fuel to boil, forming vapor
pockets that disrupt fuel flow.
7. Which of the following prevents fuel sloshing during maneuvers?
a. Refuel shutoff valves
b. Fuel ejectors
c. Baffles
d. Vent check valves
Rationale: Baffles inside tanks limit fuel movement to maintain
stability and proper pickup.
, 8. The main cause of fuel tank vent blockage is:
a. Ice crystals
b. Fuel varnish
c. Dirt, insects, or environmental debris
d. Electromagnetic interference
Rationale: Vents are exposed to the environment and frequently
clog with debris.
9. Which component maintains positive pressure in fuel tanks during
flight?
a. Dump valve
b. Fuel heater
c. Pressurization valve
d. Bypass valve
Rationale: Pressurization valves regulate tank pressure to
prevent collapse and aid transfer.
10. If a fuel tank is over-pressurized, the safety feature that
protects the structure is the:
a. Fuel quantity indicator
b. Dump valve
c. Pressure relief valve
d. Vent check valve
Rationale: Relief valves release excess pressure to prevent tank
damage.
11. What is the primary indication of fuel pump cavitation?
a. High fuel pressure
b. Fuel odor in cockpit
c. Fluctuating fuel pressure and noisy operation
d. Fuel temperature increase
Questions, Answers & Rationales
1–100
1. What is the primary purpose of an aircraft fuel system?
a. Provide lubrication to the engines
b. Cool the engine oil
c. Store and deliver fuel to the engines
d. Store, manage, and supply fuel to the engines at the correct
pressure and flow
Rationale: Aircraft fuel systems must ensure continuous, reliable
fuel flow at the correct pressure for safe engine operation.
2. Which fuel tank type is integral to the aircraft's structure?
a. Bladder tank
b. Integral tank
c. Rigid removable tank
d. Auxiliary tank
Rationale: Integral tanks are sealed sections of the aircraft wings
or fuselage used to store fuel.
3. What is the main advantage of bladder-type fuel tanks?
a. Ease of installation and maintenance
b. Highest fuel capacity
c. Lowest likelihood of leaks
d. Most resistant to contamination
Rationale: Bladder tanks can be removed or replaced easily,
reducing maintenance time.
,4. Microbiological contamination in aviation fuel is most common in
areas containing:
a. Pure fuel
b. Water and fuel interface
c. Fuel vapor
d. Additives
Rationale: Microbes thrive where water meets fuel, feeding on
hydrocarbons and causing corrosion.
5. The primary function of a fuel boost pump is to:
a. Remove water from fuel
b. Supply positive pressure to the engine-driven pump
c. Measure fuel temperature
d. Pressurize the fuel tanks
Rationale: Boost pumps ensure sufficient inlet pressure to
prevent engine pump cavitation.
6. A common cause of vapor lock in fuel systems is:
a. High temperatures causing fuel to vaporize
b. Low humidity
c. Excessive water in fuel
d. Overfilling fuel tanks
Rationale: Heat causes volatile fuel to boil, forming vapor
pockets that disrupt fuel flow.
7. Which of the following prevents fuel sloshing during maneuvers?
a. Refuel shutoff valves
b. Fuel ejectors
c. Baffles
d. Vent check valves
Rationale: Baffles inside tanks limit fuel movement to maintain
stability and proper pickup.
, 8. The main cause of fuel tank vent blockage is:
a. Ice crystals
b. Fuel varnish
c. Dirt, insects, or environmental debris
d. Electromagnetic interference
Rationale: Vents are exposed to the environment and frequently
clog with debris.
9. Which component maintains positive pressure in fuel tanks during
flight?
a. Dump valve
b. Fuel heater
c. Pressurization valve
d. Bypass valve
Rationale: Pressurization valves regulate tank pressure to
prevent collapse and aid transfer.
10. If a fuel tank is over-pressurized, the safety feature that
protects the structure is the:
a. Fuel quantity indicator
b. Dump valve
c. Pressure relief valve
d. Vent check valve
Rationale: Relief valves release excess pressure to prevent tank
damage.
11. What is the primary indication of fuel pump cavitation?
a. High fuel pressure
b. Fuel odor in cockpit
c. Fluctuating fuel pressure and noisy operation
d. Fuel temperature increase
